PEG胁迫下不同抗旱性油菜品种的生理特性及其响应机制

Physiological characteristics and response mechanisms of different drought-resistant rapeseed varieties under PEG stress

[目的]比较干旱胁迫下4个不同抗旱性油菜品种的生理指标,为进一步阐明油菜抗旱性生理机制提供参考。[方法]以4个不同抗旱性油菜品种为试材,使用质量分数为5%的聚乙二醇(PEG-6000)溶液模拟干旱胁迫,以等量蒸馏水为对照(CK)。通过培养皿试验,分析了PEG干旱胁迫对油菜幼苗生长发育、抗氧化酶活性及渗透调节物质的影响。[结果]PEG胁迫抑制了油菜的生长发育。与CK相比,强抗旱性油菜品种(青杂4号、浙油杂1号)发芽率、发芽势变化不明显,而弱抗旱性油菜品种(新游25、农家自用22号)的发芽率、发芽势则明显降低。强抗旱性油菜品种的SOD、POD、CAT、APX等抗氧化酶活性显著高于弱抗旱性品种;H_(2)O_(2)、O_(2)^(-)、MDA含量以及电导率显著低于弱抗旱性品种;可溶性糖含量则显著高于弱抗旱性品种。[结论]PEG胁迫下,强抗旱性油菜品种的抗氧化系统对活性氧的清除能力更强,正向激素、渗透调节物质含量更高,这一生理机制提高了油菜幼苗的抗旱能力。

[Purpose]To compare four different drought-resistant rapeseed varieties under drought stress using physiological indices,to further elucidate the physiological mechanism of drought resistance in rapeseed.[Method]Four different varieties of rapeseed with different drought resistance were subjected to simulated drought stress with polyethylene glycol(PEG-6000)at a mass fraction of 5%and treated with an equal amount of distilled water as control(CK).The effects of drought stress on growth and development,antioxidant enzyme activity,and the osmotic-regulating substances of rapeseed seedlings were analyzed using petri dish experiments.[Result]Rapeseed growth and development were inhibited under drought stress.Compared with CK,the germination rate and vigor of strongly drought-resistant varieties(Qingza 4 and Zheyouza 1)showed no significant changes,while those of the weakly drought-resistant varieties(Xinyou 25 and Nongjia Ziyong 22)significantly decreased compared to the CK treatment.In addition,the antioxidant enzyme activities(SOD,POD,CAT,and APX)of strongly drought-resistant varieties were significantly higher than those of weakly drought-resistant varieties.Under drought stress,the contents of hydrogen peroxide,superoxide anion,and MDA as well as conductivity were significantly lower in strongly drought-resistant varieties than those in weakly drought-resistant varieties,while the soluble sugar content in strongly drought-resistant varieties was significantly higher than that in weakly drought-resistant varieties.[Conclusion]Under drought stress,the difference between strongly and weakly drought-resistant varieties was due to the stronger ROS scavenging ability of the antioxidant system and higher levels of positive hormones and osmotic regulatory substances in the strongly drought-resistant varieties.This physiological mechanism enhances drought resistance in rapeseed seedlings.